Lab Skill 5: Echinodermates

LAB SKILL 5 ECHINODERMATES I. Basic theory The general characteristic is that when they are still larvae their bodies are bilaterally symmetrical, while when they are adults their body shape becomes radially symmetrical. In addition, this animal has a water channel which is often called a system.ambulacral. This system is used to move, breathe, or to open prey that has grafts. According to some experts, echinoderms are divided into 5 classes, namely:Asteroidea, Ophiuroidea, Echinoidea, CrinoideaAndHolothuroidea. 1.1. Asteroidea (Sea stars) The body is star-shaped with 5 arms, the dorsal or aboral surface of the body has spines of various sizes. The mouth is located in the central part of the oral surface surrounded by the peristome, the anus is small in the aboral part. The ambulacral forms a striking curve supported by podia or tube feet. Pedicelariae are small, movable spines. The function of pedicelariae is to protect the dermal gills, prevent debris and small organisms from accumulating on the body surface and also to capture food. The body support is composed of lime sheets or ossicles which are bound by musculus or connective tissue. Examples of the most widely known species arePentaceros sp, Astropecten sp, Archaster sp. 1.2. Ophiuroidea (Snake Stars) Living in coral seas, the body is shaped like a small disc ball with 5 long, round arms that can be moved. The spines are very numerous and are only found on the lateral parts of the body. In the arm there are small coelom canals, nerve trunks, blood vessels and branches of the vascular system. On the arms there are also ambulacral legs which are often referred to as tentacles which are equipped with suction devices or ampullae, sensory organs and also help with breathing which allows food to enter the mouth. All digestive and reproductive organs are contained in the disc. The mouth is located in the center of the body, surrounded by 5 lime plates which function as jaws. It does not have an anus, food waste is excreted through the mouth. Examples of species in this class include:Ophiotrix, Ophioderma, Ophiura, Ophioglypha. 1.3. Echinoidea Includes sea urchins, sand dollars, and similar, which have a disc or round shape, no arms, a long, movable spiny body, closed ambulacral grooves, sucking tube feet, and complex pedicellareae. Some types of Echinoidea have poison glands. The anus is located in the center of the body on the aboral surface located between large limestone plates that have 2, 4 or 5 genital holes. The mouth is located in the oral area surrounded by 5 strong and sharp teeth. Examples of species include:Arbacia punctulata, Echinocardium cordatum, Strongylocentrotus sp. 1.4. Holothuroidea (sea cucumber or sea cucumber) The round body is elongated with an oral to aboral line as the axis, has no arms, usually does not have an external madreporite, the tube feet are modified into oral tentacles numbering 10 – 30 tentacles that can be extended and retracted. On the ventral part of the body there are 3 ambulacral leg areas which are equipped with suckers which function to move. Examples of holothuroidea species include:Curcumaria frondosa. II. Tools and materials Tool : 1. Loope 2. Paraffin tub 3. Surgical tools Material : 1) Echinodermata Specimens III. Ways of working 1. Observe using a loop the morphological structure of sea urchins, sea cucumbers, sea stars and brittle stars. 2. Draw each specimen above and give a description and make a taxonomic classification